Device for the preparatory treatment of foil webs or strips of synthetic material

ABSTRACT

A device for the preparatory treatment of foil webs and foil strips of synthetic material in which a heated grate roller journalled unilaterally or at both ends cooperates with one or more outer pressure rollers while the grate bars or webs of the grate roller are sharp-edged at the peripheral surface of the roller and have a cross-section which increases toward the inner chamber of the grate roller and thus define free passages which toward the interior of the grate roller are of a funnel shape.

United States Patent [1 1 Koch et al.

[ DEVICE FOR THE PREPARATORY TREATMENT OF FOIL WEBS OR STRIPS OFSYNTHETIC MATERIAL [75] Inventors: Heinrich Koch, Jakobstr. 88,

Siegburg, Germany; Heinz Staneck, Siegburg, Germany [73] Assignee: saidKoch, by said Staneck,

Siegburg, Germany [22] Filed: Mar. 4, 1971 [21] Appl. N0.: 120,869

[30] Foreign Application Priority Data Mar. 5, 1970 Germany P 20 10415.8

[52] US. Cl 156/515, 83/171, 83/665,

[51] Int. Cl B32b 31/00, B27b 7/06 [58] Field of Search 156/510, 512,515, 156/582, 251; 83/663, 965, 171

[56] References Cited UNITED STATES PATENTS Kraft et a1 156/251 Nov. 20,1973 2,229,121 1/1941 Nye et a1. 156/251 3,510,380 5/1970 Bittner etal.. 156/251 3,585,097 6/1971 Beason 156/582 3,075,573 1/1963 Piazze156/583 Primary Examiner-Douglas J. Drummond Attorney-Walter Becker [5 7ABSTRACT A device for the preparatory treatment of foil webs and foilstrips of synthetic material in which a heated grate roller joumalledunilaterally or at both ends cooperates with one or more outer pressurerollers while the grate bars or webs of the grate roller are sharpedgedat the peripheral surface of the roller and have a cross-section whichincreases toward the inner chamber of the grate roller and thus definefree passages which toward the interior of the grate roller are of afunnel shape.

3 Claims, 4 Drawing Figures Patented Nov. 20,1973 I 3,773,599

v 3 Sheets-Sheet l Patented Nov. 20, 1973 I5 Sheets-Sheet :3

Patented Nov. 20, 1973 3 Sheets-Sheet 3 I DEVICE FOR THE PREPARATORYTREATMENT OF FOIL WEBS OR STRIPS OF SYNTHETIC MATERIAL The presentinvention relates to a device for the preparatory treatment of foil websor strips of synthetic material which webs or strips are subsequentlyrefined in an extruder. When producing and processing foil webs ofsynthetic material, rejects as well as waste are encountered. Inasmuchas the synthetic material does not lose its basic properties during thegenerating process, there is the general endeavor to regenerate therejects as well as the water to regain the basic material.

A number of devices have become known by means of which rejects as wellas waste can be regenerated. A heretofore known such device concerns abeater or crusher mill in which the foils or the water material isdiminished and subsequently mixed in a dry mixer until, due to theoccurring frictional heat, a granular agglomerate is formed which canagain be used as starting material. The drawback of this heretoforedevice consists in that the crushing of the foil webs or foil waste inthe beater mill as well as the processing operation in the dry mixerhave to be controlled very carefully because, for instance,polyvinylchloride (PVC) foils are extremely sensitive with regard to toohigh a development of heat because at a certain excess temperaturechemical reactions are initiated which change the character of the basicmaterial. Therefore, with this heretofore known device, the mixingoperation has to be particularly carefully controlled by the operator.

According to another heretofore known device, the foil or foil waste orresidues are melted and are subsequently further processed to form thebasic material. The melting of the foil web or foil waste can, however,be carried out only with such synthetic materials which, in view of themelting operation, will not lose their basic properties.

The drawback which is inherent to the heretofore known devices forrefining foil webs or foil waste or residues of synthetic materialconsists in that the working operations need the attention of anoperator, and furthermore the heretofore known devices are not usablefor all kinds of synthetic materials.

It is, therefore, an object of the present invention to provide a devicewhich will operate substantially automatically and continuously andwhich will be independent of the kind of synthetic material employed forthe respective foil.

This object and other objects and advantages of the invention willappear more clearly from the following specification in connection withthe accompanying drawings, in which:

FIG. 1 diagrammatically illustrates a regenerating plant according tothe present invention.

FIG. 2 illustrates on a somewhat larger scale than FIG. 1 a portion ofthe extruder of the plant of FIG. 1 together with the auxiliary devicesassociated therewith.

FIG. 3 represents a section through a grate roller for use in connectionwith the plantof FIG. 1, said section being taken along the line III IIIof FIG. 4.

FIG. 4 is a view of FIG. 3 as seen in the direction of the arrow A inFIG. 3.

The device according 'to the present invention is characterizedprimarily in that a heated grate roller which is unilaterally journalledor is journalled at both ends cooperates with one or more outer pressurerollers while the bars or webs of the grate roller are sharpedged at thesurface of the roller and have a crosssection which increases toward theinner chamber of the grate roller and thus define free passages whichtoward the interior of the grate roller are of a funnel shape.

In order to be able to heat the individual grate bars or webs, they are,according to a further development of the invention, provided with abore extending in the longitudinal direction thereof. Through thesebores heated oil or, as an alternative, resistive wires for an electricheating may be passed. The individual grate bars define free passagesthe cross-section of which may vary. Thus, according to the invention,the crosssection may be rectangular, square, oval or circular, or of anyother contour. For purposes of simplicity, the square or rectangularfree passages are preferred.

According to a further feature of the invention, a conveying means,preferably a worm, extends into the interior of the roller, and thelargest diameter of the worm is so selected that between the worm andthe inner grate roller confinement there will remain a free chamber.

Referring now to the drawing in detail, a regenerating plant for thepreparatory treatment of webs of foil of synthetic material according tothe present invention comprises a regenerating extruder 1 having aninlet 2 to which is firmly connected a funnel-shaped supply or storagecontainer 3. The connection between the extruder l and the supplycontainer 2 is effected by a flange-like intermediate member 4. In thecontainer 3 there is provided a worm 5 which tapers toward the extruderinlet 2. The worm 5 has an upwardly extending shaft 6 on which ismounted an agitator mechanism 7 for rotation with the worm 5. Worm 5with agitator mechanism 7 is driven by a motor 8 through the interposedtransmission 9. To safeguard the motor 8 in case the worm 5 isoverloaded, there is provided a limit switch 10 which in such instancewill turn off the motor 8. The foil material to be regenerated in theextruder l is first pretreated in a grate roller 11 with pressure roller12. The pretreatment of the foils l3 entering in the direction of thearrow F is effected in such a way that by means of the grate roller 11the foil web or foil strip is cut into individual sections while in viewof the continuous winding-up of the web or strip material in cooperationwith the heated grate bars, the cut off or separated sections arepressed against each other layer for layer and are fused to each otherat the cutting edges. The thus fused together sections are through thefree grate'cross-sections 14 pressed in the form of a strand into theinner chamber 15 of the grate roller and from there are conveyed intothe supply container 3 by standard tearing and conveying means. Forpurposes of checking the feeding of the material to be processed to thegrate roller, a photoelectric cell 16 is provided serving as bandchecking means. The photoelectric cell l6 is coupled to the rotary trap17 in such a way that when the band or strip tears off wherebyautomatically the supply of pretreated foil material to the container 3is interrupted, the device 17 is automatically turned on and conveysthrough a pipe line 18 connected to a nonillustrated silo, for instance,polyethylene granulate or a polyvinylchloride mixture into the container3. In this way it will be assured that the worm of the extruder 1 canalways sufficiently be supplied with synthetic material so that aburning of the material will be prevented. As soon as the web or stripof foil material is again threaded into the grate roller 11, the device17 will turn off.

If a disorder occurs in the operation of the plant or calender or if achange in the calender is to be effected, the extruder has to be stoppedfor a shorter or longer period of time. During a short interruption, thedevice 17 feeds corresponding PVC-material to the extruder. If a longerstandstill period of the extruder is necessary, there exists the dangerthat the PVC-material in the extruder will in view of the longer stay bedestroyed as far as its chemical structure is concerned and can nolonger be used. In such an instance, instead of the PVC- material, highpressure polyethylene is supplied by the device 17 which material isnon-sensitive against a longer stay in the worm. After the calender hasagain been started and strip material is again pressed into the extruderwhile the worm is in continuous operation, the oncoming PVC-materialwill press the polyethylene in the worm out of the latter. After a shortperiod of operation, it is again possible to process polyvinylchloridefoils in a continuous operation.

The material regenerated in the extruder l is discharged through anozzle head 19 in the form ofa bank and is then passed through a waterbath 20. Subsequently, the thus regenerated material is conveyed over adrying path 21 and from there is passed into a granulator 22 which iscoupled to a packing or a wrapping device which automatically closes thesack or bag 23 filled with granulate.

If the strip material directly coming from the calender is processed inthe plant according to the present invention, the strand dischargedthrough the nozzle head 19 of the extruder 1 can be directly conveyed tothe calender for the purpose of making new foils.

As shown more specifically in FIG. 4, the grate roller 11 is journalledat 3 by means ofa shaft 22. Grate roller 11 comprises bars 24 which attheir surface 25 have a sharp edge 26 and which have a cross-sectionthat increases toward the inner chamber 15 of the grate roller. Theenlargement of the cross-section of the grate bars 24, as isparticularly clearly shown in FIG. 3, extends in this embodiment over acertain length only and then remains constant. Regardless of whether theincrease in cross-section of the bars of grate roller 11 toward theinterior 15 of the grate roller is continuous over the entire thicknessof the roller or only over a portion thereof and then is constant, freepassages 28 are formed which in view of the configuration of thecrosssection of the bars 24 of the grate rollers are funnel- 'shaped ortaper. As will be evident from FIG. 4, the

bars or webs are so arranged with regard to each other that freepassages of square cross-section are formed. The arrangement of the bars24 may, however, also be such that passages of different cross-section,for instance, rectangular, oval or circular cross-section, are formed.The rectangular or square cross-section, however, is preferred. Thepressure rollers 12 cooperate with the grate roller 11 and are offsetwith regard to each other by 120 as is best seen in FIG. 3. Thereexists, of course, also the possibility to employ only one or more thanthree pressure rollers 12. A conveyor, preferably a worm l0, cooperateswith the grate roller 11. Worm extends into the interior of the grateroller and has its largest diameter D so diminished that a free space 31is formed between the worm 30 and the inner configuration 11a of thegrate roller.

The operation is as follows: The web of foil 13, for instance, a web ofpolyvinylchloride, is wound onto the grate roller 11, and in view of thecontinuously increasing layer thickness is pressed against the edges 26of the bars 24 of the grate roller whereby the foil web is cut intoindividual sections. This cutting or division is facilitated by aheating effect produced by the bars 24. Simultaneously with theseparation into individual foil sections at the edges 26 of the webs orbars 24, a fusing of the individual superimposed layers takes placewhich is aided by the corresponding configuration of the bars 24 and theformation of tapered free passages 28. During the continuous winding-upof the foil web 13 onto the grate roller 11 and the thus inherentseparation of the web 13 into separate sections, individual strands 34(FIG. 3) are formed which move through the free passages 28 of the grateroller 11 into the interior chamber 15 of the grate roller. Here theindividual strands are grasped by the worm 30 and are divided intoindividual package-like structures and are subsequently conveyed to asupply or further processing station.

The heating up of the grate rollers may be effected in any suitablemanner. For instance, the bars 24 may be provided with bores 35 throughwhich heated-up oil is passed or into which heated-up rods or wiresextend. The temperature of the grate bars 24 is such that the working ofthe foil is effected at temperatures of from to C.

In this way foil bands of any width can be processed. Prior to the bandshitting the grate rollers 1 l, the bands 13 must be laterally gatheredif they are wider than the width of the grate roller. These steps,however, can be easily effected.

It is also advantageous that the entire winding-up and separatingprocess can be so coupled with the discharge step that no more materialis discharged than is wound up and divided into sections.

It is, of course, to be understood that the present invention is, by nomeans, limited to the construction shown in the drawings but alsocomprises any modifications within the scope of the appended claims.

What we claim is:

1. A device for the preparatory treatment of foil webs and foil stripsof synthetic material for subsequent regeneration in an extruder, whichincludes: a rotatable grate roller having grate bars which aresharp-edged at their peripheral outer surface and increase incrosssection from their peripheral sharp edges in radial inwarddirection whereby adjacent grate bars define funnel-shaped passages, andmeans associated with said grate bars for heating the same, said grateroller having an inner axial chamber, and helical conveying means beingsuch as to confine a free annular space with the wall of said innerchamber.

2. A device according to claim 1, in which said grate bars are providedwith bores extending in the axial direction of said grate roller andadapted to receive heating means.

3. A device according to claim 1, in which roller portions adjacent tosaid grate bars define passages of sub stantially rectangularcross-section.

l I! l

1. A device for the preparatory treatment of foil webs and foil strips of synthetic material for subsequent regeneration in an extruder, which includes: a rotatable grate roller having grate bars which are sharp-edged at their peripheral outer surface and increase in cross-section from their peripheral sharp edges in radial inward direction whereby adjacent grate bars define funnel-shaped passages, and means associated with said grate bars for heating the same, said grate roller having an inner axial chamber, and helical conveying means being such as to confine a free annular space with the wall of said inner chamber.
 2. A device according to claim 1, in which said grate bars are provided with bores extending in the axial direction of said grate roller and adapted to receive heating means.
 3. A device according to claim 1, in which roller portions adjacent to said grate bars define passages of substantially rectangular cross-section. 